It is becoming increasingly common to see mobile robotic appliances around the home or office environment. Typically these robotic appliances are in the form of robotic floor sweepers or vacuum cleaners. Examples of known robotic vacuum cleaners are the Roomba™ range of machines manufactured by iRobot Corporation, the Navibot™ range of machines manufactured by Samsung, and the Electrolux Trilobite™, which is described in part in WO97/40734. It is notable that the vacuum cleaner in WO97/40734 includes its heavier components such as the electronics and vacuum motor in a rearwards portion of the housing whilst the dirt collecting chamber is located in a forward portion of the housing, with reference to its normal direction of travel.
A robotic vacuum cleaner is required to travel around an environment treating the floor as it goes. A home or office may not have entire floor space on one level so there may be various undulations and transitions that a robot must be able to negotiate in order to perform its task effectively. For example, there may be a small vertical step between rooms and/or between types of floor coverings within the floor space. Also, the robot may be required to climb onto a temporary floor covering such as a rug.
The ‘climbing ability’ of a domestic mobile robot depends on a large extent on its overall configuration. It will be appreciated for example that if a robots centre of mass is biased significantly towards a rearward portion of the robot there is a risk of the robot becoming ‘beached’ whilst negotiating a transition. This may affect vacuum cleaning robots which are configured such that their heavier components such as vacuum motor, battery and electronics are housed in a rear portion of the machine, whilst its relatively light components such as a dirt collecting bin are cited towards a forward portion of the machine. Such a configuration is apparent in WO97/40734.